Auxiliary tip fuel tank



2 Sheets-Sheet l Q @m \m R m a Q R Q \w my L p U //K///// 4 f mm m UM WWW Mb A f m n 0 M W 7 m W v u U N a 6 0 F. N K M H Aug. 17, 1954 w. s. FLETCHER AUXILIARY TIP FUEL TANK Filed Dec. 6, 1948 17, 1954 w. s. FLETCHER AUXILIARY TIP FUEL TANK 2 Sheets-Sheet 2 Filed Dec. 6, 1948 Patented Aug. 17, 1954 messes AUXILIARY TIP FUEL TANK Wendell S. Fletcher, South Pasadena, Calif., assignor to Fletcher Aviation Corporation, Pasadena, Calif a corporation of California Application December 6, 1948, Serial No. 63,822

18 Claims.

This invention relates generally to receptacles of the closed type, and more particularly to an auxiliary fuel tank for use on aircraft. Specifically, the invention pertains to a fuel tank adapted for attachment to the exterior of an airplane, such as, for example, the Wing tip.

Conventional fuel tanks mounted on the Wing tips of airplanes are made of streamline shape in order to reduce the aerodynamic drag or resistance to the forward motion of the craft. It is the usual practice to construct such fuel tanks in two parts, that is, with upper and lower shells, each having a perimetrical head which is Welded to the bead of the other shell. Such a projecting bead-weld impairs the streamline eifect and thus produces a parasitic drag tending to reduce the speed of the airplane. Since such wing-tip fuel tanks are used primarily in military aircraft of the fighter types, which are designed to attain extremely high speeds, it is imperative that the parasitic drag be reduced to a minimum. It is therefore an important object of this invention to provide an auxiliary fuel tank which is so constructed that it has a smooth, continuous, streamlined outer surface or skin, free from projections which might otherwise cause drag tending to reduce the speed attainable by the airplane to which the tank is attached.

Another object of the invention is to provide an auxiliary fuel tank which is composed of a plurality sections capable of being assembled in end-to-end relationship, one of the scum ponents being in the form of a conoidal shell and constituting the nose section, and another of said components being constructed as a similar but more conical tail section or shell.

Another object is to provide clamping means of the tensi 11 type, disposed entirely within the tank, for clamping the several. sections in assembled relationship. The latter object is best attained by providing strut members within the nose and tail sections or shells, and clamping means insertable through an axial opening in the tail section and engageable with said strut members for drawing the same toward each other so to clamp the several sections in end-to-end abutting relationship. A related object is to provide clamping means which comprises a spindle adapted to pass through an axial hole in one strut member and having a screw-threaded end capable of being screwed into a threaded hole in the other strut member, the spindle also having a rotatable collar thereon which is adapted to be moved axially into engagement with said other strut member in response to rotation of the pair of crossing strut elements, each spindle so as to draw the nose and tail sections toward each other and thus clamp the several sections of the tank in assembled relation.

Another object is to provide a clamping spindle which has its rearward end disposed adjacent the rear end of the tail section so as to be readily accessible, said end of the spindle being of polygonal shape to adapt it to be readily rotated by a wrench or other tool.

Another object is to provide closure means for sealing the opening in the tail section through which the clamping spindle is inserted, said closure means consisting of a cap fitting within the opening and having an annular flange engageable with the end of the section, a bolt on the cap being screwed into a threaded hole in the rear end of the spindle to retain the cap in place.

Another object is to provide a tank, of the character referred to, which embodies means for positively sealing the joints between the several sections so as to produce a tank which is fluid tight.

Another object is to provide, in a tank of the type indicated, strut members consist of a engageable with a 'ing secured to the inner surface of the nose or tail section so as to afford maximum bearing engagement without reducing the fuel capacity of the tank.

A further object is to provide centering means for locating and retaining the several sections in exact axial alignment.

A still further object is to provide a tank, of the type referred to, having means by which it can be readily attached to or removed from the exterior of an aircraft.

It is customary, particularly during military conflict, to transport the auxiliary fuel tanks to the combat zones in linocked-down condition so as to conserve shipping space, the components of the tanks being assembled by mechanics at the air fields. Due to the complexity of the assembly operations, considerable time is consumed, it being necessary to expend approximately twentyeight man hours to assemble a single auxiliary In an eiiort to reduce the time involved in assembling such fuel tanks in combat theaters, the military Air Force has recently expressed the desire to obtain a fuel tank which can be assembled on the field within the prescribed limit of two man hours. It is therefore an important object of this invention to provide an auxi 'ary fuel tank, the parts of which can be assemb ed easily and quickly so as to expedite the 0 ing of the tank and its installation on an airplane.

In accordance with the present invention, the improved auxiliary fuel tank is so constructed that its components can be completely assembled in fifteen man minutes, thus effecting a tremendous saving in time which is extremely important to the military, especially during war.

Further objects will be apparent from the following specification and from the drawings, which are for the purpose of illustration only, and in which:

Fig. l is a side elevational view of a wing-tip fuel tank constructed in accordance with the present invention, the wall of the tank being broken away to better illustrate the internal parts;

Fig. 2 is a cross-sectional view, taken on line 22 of Fi 1;

Fig. 3 is an enlarged, fragmentar sectional View of the sections of the tank, showing them in disassembled relationship;

Fig. 4 is an enlarged detail of the intermediate screw-threaded portion of the clamping spindle and the collar mounted thereon;

Fig. 5 is an enlarged detail of the combined centering and sealingmeans;

Fig. 6 is a perspective View of an auxiliary fuel tank of alternative construction, the parts of the tank being shown indisassembled relationship and partly broken away to disclose the interior thereof;

Fig. '7 is a cross-sectional view, taken on line 1-4 of Fig. 6;

Fig. 8 is a transverse sectional view, taken on line 8-8 of Fig. '7, showingthe construction of the adjoining circular edges of the nose and succeeding tank sections which are clamped tcgether;

Fig. 9 is a sectional view similar to Fig. 8 but illustrating an alternative sealing means; and

Figs. 10, 11, 12, and. 13 are perspective sectional views showing modified versions of the sealing means used between the edges of adjacent sections of the tank.

Referring to Figs. 1 through 5 of the drawings in detail, the improved wing-tip fuel tank ill comprises a nose section II, an intermediate tubular section or body 12, and a tail section it, these components being assembled by means, to be hereinafter described, to produce a tank of streamline contour.

The nose section II consists of a sheet metal shell of conoidal shape which has an open base end. Placed within the open base end of the shell H is a ring l5 which extends axially from the shell as shown best in Fig. 3. Surrounding the projecting end of the ring 15 and suitably secured thereto is the outer portion H3 of an annular flange member H. The member ll is substantially channel shape in cross section and provided with walls defining an annular recess or seat IS in which is disposed a resilient, cornpressible sealing ring l9, commonly referred to as an 0 ring.

The intermediate section 12 is also constructed from sheet metal and is in the form of a frustum having its larger end of the same diameter as that of the open end of the nose section H, to adapt it to match therewith. An annular flange member 2a is suitably secured to the larg r end of the intermediate section l2 and has an annular extension or ridge 2| which is adapted to be received in the seat l8 of the flange member I! so as to locate and retain the two sections ii and i2 in axial alignment, the sections being clamped together'in this relationship, by means 7 oi the tail section,

a to be later described, so that the sealing ring :9 is compressed by this action. At its rearward smaller end, the intermediate section 52 has an annular flange member 23 which is provided with walls defining an annular recess or seat 2% which is disposed a resilient compressible se 1-- ing ring 25, this flange member being similar to the flange member ll, previously described.

A pair or" arcuate reinforcing 2i and 2t, preferaely made from 2 sections, e. i) are provided with pads disposed against e in ner surface 1 the upper portion of the intermediate section 22 and secure thereagainst by means of bolts 29. The arcuate reinforcing hers 2'? and 28 are in the form of ribs and e1.- tend throughout substantially one half of the circumference or" the section 52 shown in 2. Secured. outer surface of the section hangers 3t and ti which are ernp means for attaching the fuel tank of an airplane.

The tail section is constructed fro. metal in the form of a conoidal shell, the die eter of the case p rtion being equal to that of the smaller end of the intermediate section. to adapt it to match therewith. Secured within the larger end or" the tail section a ring which projects beyond the end of the section to receive an member id. The flange member 35 has an annular ridge or tongue 35 'adapte to enter the annular seat or recess 2 or" the flange when te intermediate and tail sections and i3 are assembled, so as to retain these sections alignment and c inpress the sealing ring 25.

At its rear apex end, the tail section it is provided with an access opening 38 which is deiined by inwardly directed annular wall 39. The access on is nor-ma V closed by means of a once closure member or cap having an annular flange abutting against the rear end or" c section it and a reduced tion 42 dispose in the opening. groove in the portion =32 receives a resilient sealing ring 33 which. engages the wall it of the o ing 38 to provide iluid tight joint. The has an axial hole for receiving a bolt t l is employed the ma ner to be later e to retain the cap in the opening rearward of the tail section is. r ward end face of the it is pref by conical tip meinb 3: :li which the bolt i l with its base seated a nut i i being screwed the bolt to manner in The several sections 3, i2, and it of the tank iii are drawn together in axial engagement and retained in this relationship by clamping n ans to be next described. Disposed wi 2n section l i is strut means .5 preferably consists of a pair of crossing struts or clamping elements it and ell. The ends of the strut elements 35 and ill are somewhat pointed (Fig. 2) and are recessed to adapt them to engage against the inner end of t. .e ring is of the nose section H. The strut elements ll and have aligned axial holes is and th element has a nut 53 secured against forward face in alignment with the holes it. If desired, only a single strut element may be employed, although I prefer to use two as described. Also, the form of the strut means may be varied as desired.

Disposed within the tail section is is similar strut means 5! which consists of a pair of crossing strut or clamping elements 52 and 53 of the same general character as the elements 45 and 41 described above, the elements 52 and 53 having aligned axial holes 54 therein.

A relatively long clamping spindle 60 is adapted to be inserted through the opening 38 and to pass through th ali ned holes 54 and 49 of the respective strut members 5| and 45. The spindle 68 has an inner screw-threaded end 6| adapted to be screwed into the nut 59 carried by the strut element 46. At its outer extremity, the spindle 60 is made polygonal in shape so as to provide, in efiect, a bolt head 62 which may be readily engaged by a socket wrench (not shown), inserted through the opening 38 to rotate the spindle. At a point intermediate its ends and located adjacent the rearward machined face of the strut element 52 the spindle is provided with a peripherally grooved portion 63 (Fig. 4). Disposed on the spindle 69 is a sleeve-like abutment collar 35, one end of which is adapted to engage the rearward face of the strut element 52. The collar 65 is slid onto the spindle 8G to overlie the grooves 64, and thereafter its tubular wall is indented from the outside to provide inwardly directed lugs 6'! engageable in the grooves to retain the collar in place.

To assemble the three sections ll, 12, and I3 to provide the fuel tank It), the strut member 65 is first located within the nose section ii, against the ring 15 thereof. The larger end of the intermediate tubular section 22 is then placed against the open rearward end of the nose section I! with its tongue 2! disposed in the seat is. In a like manner the strut member 5! is installed in the tail section [3 and the open end. of the tail section is placed against the smaller rearward end of the intermediate section I2, with the tongue 35 entering the annular seat 24. After the three sections have thus been disposed in axial abutting relationship, the clamping spindle 50, with the collar 65 mounted thereon, is inserted through the access opening 38 and passed through the aligned holes 54 and 49 of the strut members 5! and 45. The inner threaded end 5! of the spindle 60 is then screwed into the threaded hole of the nut 50 secured to the strut element 46 so that by rotating the spindle, by means of a socket wrench, the spindle is screwed through the nut. During such rotation of the spindle Ell, the end of the collar 65 firmly engages the rearward face of the strut element 52. The result of this action is to draw the two strut members 5! and 45 toward each other so as to cause the tank sections ii, 52, and [3 to b firmly clamped together. In order to reduce friction to a minimum, an anti-friction thrust bearing 66 may be interposed between the strut member 5! and the collar 5, if desired.

It is thus seen that the single clamping spindl 59 serves to draw the sections together with sufficienlt force to compress the sealing rings !9 and 25 so as to provide leak-proof joints between the sections. It will also be apparent that, due to the engagement of the tongues 2| and in the respective annular seats [8 and 24, the sections are automatically positioned and retained in axial alignment.

After the sections of the tank have been assembled in the manner explained above, the rear or aft end of the tank is closed by means of the cap All which is inserted into the opening 38 with its flange 4i abutting the end of the section 3. The bolt 44 is then inserted through the cap and its inner threaded end screwed into a tapped hole 70 in the rearward end of the spindle 59, the end of the spindle entering a counterbore of the cap to aid in centering these parts. Due to the sealing ring 43, the tank Iii is sealed at the opening 38 to prevent leakage of liquid fuel there through. The tip member ii is then attached to the end of the section l3, and the resulting fuel tank I0 is of streamline contour. Since its outer surface is free from protuberances, the tank will create a minimum amount of drag, and this will not reduce the forward speed of the airplane, to which the tank is applied, to any appreciable extent.

The present fuel tank I 0 may be provided with accessories common to receptacles of this character, such devices not being herein disclosed in detail, since they form no part of the invention. Sufiice it to state that the tank has a iller opening 15 in the nose section ii through which the liquid fuel can be poured into the tank, the opening being normally closed by a filler cap 16. The tank 50 is also provided with the usual delivery tubes 1'! and 78 whose ends are disposed within a strainer device 19, and a vent tube til.

Referring now to Figs. 6 to 12 of the drawings. the present invention further contemplates a slightly modified construction of the auxiliary fuel tank and several alternative constructions of the tank sealing means. The auxiliary fuel tank shown in Fig. 6 includes a nose section 9!, a pair of intermediate sections '32 and 53, and a tail section 94. The nose section 9% is conoidal in shape and to the rim of its rearward open end is suitably secured a clamping annulus Q5 which has a peripheral recess for receiving the edge of the nose section and an annular inner recessed portion Bl in which an 0 type sealing ring 58 is disposed (Fig. 8). Between the two recesses es and ill, the annulus is formed with an intermediate annular recess SS. Secured within the open end of the nose section 5.! is a pair of cross strut members and it! which are in the form of bars having curved shoe portions M2 at their ends. The strut members Hill and mi are adapted to extend across the interior of the nose section 9!, as shown in Figs. 6 and '7, with their curved shoe portions fitting snugly in the annular recess of the clamping annulus Each strut member 1% and it?! is provided witi ho s at each of its ends, each boss having a tapped hole its which is used for the purpose to be hereinafter e7;- plained.

The first tubular intermediate section .s substantially cylindrical in shape, and at its forward end it carries a ring which, shown in Fig. 8, has an inner portion or tongue of arcuate cross section, this portion being adapted to enter the inner recess 2? of the annulus when the two components :35 and Q2 are drawn axially together, so as to corn ress the sealing ring 58 which is preferably made from synthetic rubber. By this means a leak-proof connection. is established between the compone ts e At its other end, the intermediate section 2 carries an annulus Isl which is of same co".- struction as the annulus 35 previously desc- .oed and which has an inner recess or seat in which an 0 type sealing ring is disposed, these entities being the same as those shown in connection with the annulus and therefore not disclosed in detail.

The second intermediate section 33 is of frustoconical shape, and at its larger forward end it carries a ring H0 which is similar to the ring H35 described before. Disposed in the rearward side of the ring HE are the curved shoe portions H! of strut members H2 H3 which have apertures ii l therein. which are adapted to align with the tapped holes of the strut members lilii and tell when the tank is assembles. Extending at right angles between the strut members H2 and H3 with its ends secured thereto is a bar H5 having a central boss provided with threaded apertur i it. At its rearward end, the intermediate section as has an annulus ll"? of the sam construction as the and as"; described above.

tongue at the new ing the respective recess or seat provided in the rearward end of each section thereof. After the sections 3i, and been arrange in the order named above, 529 are in erted through the rearward open e of the section 523 and passed through the apertures lid of the strut members H2 H3, the forward threaded ends of the tie-rods are screwed into the tapped holes With the tie-rods iii! thus inserted, nuts 525 are screwed onto their rearward threaded ends and set up against the rearward side of the strut ember the result of this action being to dra v the secions 92, and Q3 firmly together and to compress the sealing rings to provide leak-proof connections. The tierods i253 are substantially equally spaced and provide a. co nection which effectively resists stresses and so lllS to which the auxiliary tank might be subjected. It is apparent that any suitable number of intermediate sections such as those shovm at 532 and 9:3 may be 'eineployed to produce an auxiliary fuel tank of the required capacity.

The tail section Q-l, which is at ached to the rearward end of the section is of conoidal shape and carries a ring i225 which is similar to the ring ltd, previously described, and which is adapted to compress a sealing (not nown) in the annular seat of the annulus i it when the components 93 and t l are drawn together in the nanner to be later explained. Extending across the open forward end of the section 9 t wit.-- its ends suitably secured to the ring E is a cross strut member or bar lit having a central aperture 22? through which a clamping rod 523 is adapted to pass alter being inserted through an access opening in the rearward end of the tail section as. The clamping rod 628 is similar to the clamping rod 5% disclosed in Fig. and therefore it is not described in detail. Suffice it to state that the rod 23 has an inner screw-threaded end adapted to be screwed into the tapped hole H6 and carries a collar ifiil is identical with, and which is applied to use in the same manner as, the collar draw the tank sections 93 and firmly together. A cap 53!, similar to the cap id, is employed to close the access open ng of the section and a bolt i32 screwed into a tapped hole in the outer end of the rod E23 secures the cap in closed position, the cap being enclosed by a conical tip member E33.

It will be apparent that the auxiliary fuel tank so is similar to the tank shown in Figs. 1 to 5 but is provided with additional intermediate sections so that the capacity of the tank can be readily varied to meet the requirements by adding or subtracting sections, it being noted that the only change required is in the tie-rods 52o which may be furnished in appropriate lengths to suit the conditions. Due to the increased length of the auxiliary fuel tank Bil, it has been found desirable to employ means in addition to the single central clamping spindle, shown in Fig. 3, and in the modified structure this additional means consists of the tie-rods lZil which can be easily and quickly inserted through the open rearward end of the rearmost intermediate section, such as, for example, the section 93, prior to the attachment of the tail section ea. As in the structure disclosed in Fig. 3, the auixiliary fuel tank Eli can be completely assembled on the field in a few man minutes, and thus constitutes an important improvement over conventional fuel tanks which require many man hours to assemble them.

Referring now to Fig. 9, the invention contemplates sealing means between the sections of the tank which are exceptionally strong and rigid, this alternative structure including an annulus E35 carried by one section 35 and a ring i3? carried by the adjacent end of another section 538. lhe ring l3? has an annular bead or tongue iilil which is adapted to enter and compress a sealing ring l lo disposed in a seat ill of the annulus I35, the sections 536 and ifiil being drawn together by tie-rods 52 which pass through apertures M3 in the ring with their threaded ends screwed into tapped holes in the annulus 135.

In the alternative construction shown in Fig. 10, the tank sections Hi5 and Hill are provided with respective sheet metal rings Hi? and M3 which are of channel shape cross section, the ring Hi1 being adapted to enter the ring Hi8 to compress a sealing ring ma therebetween.

In the modified construction shown in Fig. 11, the means for compressing the sealing ring Hill is provided on the tank sections Edi and E52 themselves, the section H52 having an annular flange i53 formed with a ledge ills upon which the ring W3 is seated. The tank section it! has an inturned flange 25-5 which engages the sealing ring I58 to compress the latter as the tank sections are drawn together.

Fig. 12 illustrates a further modified structure in which one tank section 558 has a channel shaped annulus l59 providing an annular seat Hill for receiving a sealing ring Hit. The other tank section N52 has an inturned flange 53 adapted to engage the sealing ring l il to compress the same.

A still further modified tank sealing means is shown. in Fig. 13. In this construction one tank section i provided with a ring 5655 of V- shape cross section, a compressible sealing ring it? of circular cross section being carried by the ring 665. The other tank section tilt has an inner annulus its of angular cross section, the annulus having a lower lateral leg ll'il which underlies the lower portion of the ring Hi5. When the two sections I65 and E53 are drawn together, the sealing ring it! is compressed between the ring 5 and the annulus 58 to provide a liquidtight seal.

It will be understood that clamping means other than the spindle 55 or 28 and the tie-rods 12!) may be employed, it being within the concept of this invention to provide various forms of clamping means of the tension type, such as turnbuckles engageable with tie-rods or other means detachably connected between certain of the tank sections, for the same purpose.

While the improved fuel tank has been herein disclosed as embodied in several preferred forms of construction, by way of example, it will be apparent that other changes and modifications might be made therein without departing from the spirit of the invention. Consequently, I do not wish to be limited in this respect, but desire to be afforded the full scope of the appended claims.

I claim as my invention:

1. A streamlined fuel tank, comprising: at least one tubular member; a first generally conical shell member having an open end disposed against and abutting one end of said tubular member and having a closed end; a second generally rrustoconical shell member having an open end disposed against and abutting the other end of said tubular member and provided with a port at its other end; first and second strut means disposed entirely within and in engagement with said first and second shell members, respectively, and ad- J'acent the open ends thereof; clamping means entirely within said tubular and shell members and extending through tubular member and engaging said strut means and drawing said strut means toward each other so as to clamp said shell members and said tubular member in end-to-end relationship, said clamping means being accessible through said port; and a closure member in said port closing the same.

2. A streamlined fuel tank, comprising: at least one tubular member; a first generally conical shell member having an open end disposed against and abutting one end of said tubular member and having a closed end; a second generally frustoconical shell member having an open end disposed against and abutting the other end of said tubular member and provided with a port at its other end; first and second strut means disposed entirely within and in engagement with said first and second shell members, respectively, and ad- .iacent the open ends thereof; screw means entirely within said tubular and shell members and extending through said tubular member and engaging said strut means and drawing said strut means toward each other so as to clamp said shell members and said tubular member in end-to-end relationship, said screw means being accessible through said port; a closure member in said port closing the same; and additional screw means extending through said closure member and engaging means within said tubular and shell members for securing said closure member in said port.

3. A fuel tank as defined in claim 1 in which said strut means engage in abutment against the inner edges of rings secured to and disposed within said shell members.

4. A fuel tank as defined in claim 1 and including sealing means interposed between each of said shell members and said tubular member and between said shell members and said closure member so as to render said fuel tank fiuid tight.

5. A fuel tank as defined in claim 1 in which each of said shell members has an internal flange adjacent its open end and said tubular member has internal flanges at its opposite ends engaging said internal flanges or" said shell members.

6. A fuel tank as defined in claim 1 in which each of said shell members has an internal fiange adjacent its open end and said tubular member has internal fianges at its opposite ends engaging said internal flanges of said shell members, and including compressible sealing rings disposed between said interengaging flanges.

7. A fuel tank as defined in claim 1 in which each of said shell members has an internal annular flange adjacent its open end, and said tubular member has internal annular fianges at its opposite ends engaging said flanges of said shell mem- 10 here, one of the flanges of each interengaging pair of flanges having an annular recess therein, and a compressible sealing ring disposed in each of said recesses and compressed by the clamping of said tubular and shell members together so as to render said fuel tank fluid tight.

8. A fuel tank as defined in claim 1 in which each of said shell members has an internal annular fiange adjacent its open end, and said tubular in saber has internal annular flanges at its oppoe ends engaging said flanges of said shell mems, one of the flanges of each interengaging pair es having an annular recess therein, and

' of said fianges of each pair of interfianges having an annular ridge reengaging said ridge in response to the clamping bular and shell members together so sed by said tu render said fuel tank fiuid tight.

9. A fuel tank as defined in claim 1 in which each of said strut means includes a pair of crossing elements having their ends engaging rings secured to and disposed within said shell members.

10. A fuel tank, comprising: a tubular member; a first generally conical shell member having an open end disposed against and abutting one end of said tubular member; a second generally frusto-conical shell member having an open end disposed against and abutting the other end of said tubular member and provided with a port at its other end; a first strut member disposed entireiy within and engaging said first shell memher, said first strut member having an axial screw-threaded hole; a second strut member disposed within and engaging said second shell member and having an axial hole; a clamping spindle extending through said port and through said hole of said second strut member, said spindle having a screw-threaded end screwed into siad threaded hole of said first strut member and an intermediate peripherally grooved portion; a collar rotatable on said grooved portion of said spindle, said collar engaging against a side of said second strut member and causing said strut members to be drawn toward each other to clamp said tubular and shell members together; sealing rings compressed between the abutting ends of said tubular and shell members; and a closure member in said port closing the same.

11. A fuel tank as defined in claim 10 in which the end of said spindle opposite said threaded end is disposed within said second shell member adjacent said port and provided with wrenchengaging means by which said spindle can be rotated.

12. A fuel tank as defined in claim 10 in which the end of said spindle opposite said threaded end is disposed within said second shell member adjacent said port and provided with an axial threaded aperture, said closure member having an axial hole therein, said fuel tank also including a bolt having a head abutting the outer end of said closure member and a shank extending through said axial hole and screwed into said threaded aperture to draw said closure member firmly against the end of said second shell member.

13. A fuel tank as defined in claim 10 in which said tubular member is frusto-conical in shape so that one end thereof is of greater diameter than the other end thereof, said first shell memher being of conoidal shape and joined to the end of said tubular member of gerater diameter,

. and-said second shell member being of conoidal. I shape and joinedto the end of said tubular member of lesser diameter, said second shell member be ng of greater conicity than said first shell member, said shell members and said tubular member together providing a fuel tank of streams lined. contour.

14. A fuel tank, comprising: a first shell member having an open end and provided with a first cross strut means therein; a plurality of tubular members, said first shell member and said tubular members being disposed in axial alignment with their open ends in abutting relationship, the tubular member disposed most remotely from said first shell member being provided with a second cross strut means therein; a plurality of first clamping means extending longitudinally within all of said members and engaging said first and second cross strut means for retaining said shell member and all of said tubular members in connected relationship; a second shell member having an open end engaging the end of said most remotetubular member, said second shell member having a thirdcross strut means therein; compressible sealing means disposed be tween the several abutting ends of all of saidmembers for rendering the tank leak-proof and a second clamping means connected between said third and said second cross strut means for retaining said second shell member in aligned abutting relation to said most remote tubular member.

15. A fuel tank; comprising: a first shell memer having an open end and provided with a first cross strut means therein; a plurality of tubular members, said first shell member and said tubular members being disposed in axial alignment with their open ends in abutting relationship, the tubular member disposed most remote from said first shell member being provided with a second cross strut means therein; a plurality of first clamping means insertable through the end of most remote tubular member and extending longitudinallywithin all or said members and engaging said first and second cross strut means for retaining said first shell member and all or" said tubular members in connected relationship; a second shell member having an open end engaging the end of said most remote tubular member, said second shell member having a third cross strut means therein and a port in itsother end; compressible sealing means disposed between the several abutting ends of all of said members for rendering the tank leak-proof; a second clamping means insertable through said port and connected between said third and said second cross strut means for retaining said second shell memher in aligned abutting relation. to said most remote tubular member; and a closure member insertable in said port for closing the same.

16. A fuel tank as defined in claim 15 in which said first cross strut means has a plurality of screw-threaded holes, and in which said second cross strut means has a like number of apertures aligned with said screw-threaded holes, said first clamping means including a plurality of tie-rods each having a first threaded end screwed into one of said screw-threaded holes and a second vided with an internal annular recess, and in which said first and second cross strut means comprise bars extending transversely of said first shell member and said most remote tubular member and having curved shoe portions engaged in said annular recesses.

18. A fuel tank as defined in claim 15 in which said first clamping means engages said first and second cross strut means at points disposed adjacent the inner surfaces of the peripheral walls of said first shell member and saidmost remote tubular member.

References Cited in the file of, this seat UNITED STATES PATENTS Number. W Name Date 643,787 Brouchu -1- Feb. 20, 1900 783,776 Cornell Feb. 28, 1905 1,169,084 Brouchu Jan. 18, 1916 1,181,636 Bouget May 2, 1916 1,522,539 Ireland Jan; 13, 1925 1,549,153 Schefi": Aug. 11, 1 925 l,87,637 Conway June 26,1928 2,375,858 Makaroff -1 May 15, 1945 2,383,065 Lehman Aug. 21, 1945 2,383,864l Bechman Aug. 21, 19 15 2515395 l-lumphreys Feb. 11, 1947 2,471,295 Allen et al. May 2 5.19%

FOREIGN PATENTS Plumber Country Date 28,743 Great Britain of 1897 5,103 Great Britain of v1905 212,407 Great Britain Mar. 13, 1924 578,769 Germany June 17,1933 

